When is very slow driving particularly dangerous?

Very slow driving can be particularly dangerous in both scenarios described. When approaching the crest of a hill, drivers may not be able to see what’s coming over the top. If a vehicle is traveling much slower than the speed of traffic, it can lead to unexpected and potentially hazardous situations for drivers who cannot see the slow-moving vehicle until it's too late to react safely. This is because vehicles behind may not anticipate the slower speed and may not have enough time to adjust or safely change lanes.

Similarly, when rounding a curve, visibility can be limited. If a vehicle is moving significantly slower than others, it can create a sudden obstacle. Other drivers may not have enough time to react, leading to possible rear-end collisions or other accidents. The combination of these factors, including limited visibility and changes in speed, makes very slow driving particularly dangerous in these situations. Therefore, driving slowly just after a hill or around a curve requires heightened awareness and caution to ensure safety for all road users.